Long yardage tape core



March 13, 1962 R. c. MIX

LONG YARDAGE TAPE CORE 2 Sheets-Sheet 1 Filed April 20, 1960 P0554 7 C. M:

Filed April 20, 1960 R. C. MIX

LONG YARDAGE TAPE CORE 2 Sheets-Sheet 2 3,Z5,l5 Patented Mar. '13, 1962 ffic 3,025,015 LONG YARDAGE TAPE (IORE Robert C. Mix, Fat. Paul, Minn, assignor to Minnesota Mining and Manufacturing Company, St. Paul, Minn, a corporation of Delaware Filed Apr. 20, 196i), Ser. No. 23,486 Claims. (Cl. 242-58.5)

This invention relates to a tape core on which tape is wound in roll form and more particularly relates to a new and useful tape core particularly designed for winding tape in roll form in long yardages.

With the advent of automation in packaging and increased use of tape in bundling wood, iron, and other structural items there is increased need for tape wound in continuous long yardages and particularly there is increased need for supplying tapes in such yardages. Tapes wound into ordinary radially wound rolls, i.e. wound about a single axis, in long yardage lengths and large diameters, e.g. 700 yds, and longer and diameters larger than about 15 inches, are awkward to store and handle, as well as use, the possibility of undesirable fly wheel action taking place being greatly increased as the roll diameter increases. As used in this invention, the term radially wound is used to describe a tape web spirally wound upon itself on a common radial plane from a radius or radii emanating respectively from a single axis or from a plurality of axes.

Level wound rolls, namely tape wound in reversely spiralled layers on elongated cylindrical cores provide long yardage rolls of tape which are compact and which will dispense long yardages without presenting handling, packaging and storage problems. However, in these level wound rolls, the edges of the tape roll are not as densely packed as the remaining portion through the center of the roll which tends to result on long time storage in unsightly edge wrinkling and may additionally cause excessive adhesive degradation due to exposure to the elements and embrittlement of the tape layers at the edges of the roll. Another problem with spirally wrapped, level wound rolls occurs when a filament tape, e.g., a pressure sensitive adhesive tape having a backing comprising a multiplicity of aligned filaments of glass, nylon, or the like, bonded to one another, is spirally wound on such a roll. As the filament tape is dispensed from the roll, each cross-over point of the tape strip as it is unwound from the roll over the reversely spiralled winding of the next lower layer creates a point wherein the adhesive of the strip being unwound tends to pick up and carry with it an edge filament of the next lower tape layer. Once picked up, the edge filament separates easily from its adjacent backing filaments and begins to ravel away from the lead angle at which the tape is being dispensed from the roll. This ravelling can severely interfere with the tape dispensing and packaging from the roll and create work stopping interruptions by fouling the dispensing machinery.

This invention provides a long yardage tape core upon which tape can be wound which combines the advantages of the level wound roll long yardage tape capacity and handling ease with the dispensing ease of short yardage radially wound tape rolls.

A long yardage tape core formed in accordance with this invention has an outer surface comprising a plurality of eccentric continuous tape winding surfaces disposed in side by side relation with one another and upon each of which tape can be radially wound in roll form, the major are (that with the longer radius) of adjacent eccentric winding surfaces being disposed diametrically opposite one another whereby as tape is radially wound on one eccentric surface to a height on the minor are thereof (that with the shorter radius) equal to the height of the major arc of the adjacent eccentric winding surface the tape web can be smoothly crossed over to such adjacent winding surface and radially wound therein while preserving tape web continuity.

A preferred form of long yardage tape core made in accordance With this invention will now be described in conjunction with the accompanying drawings wherein:

FIGURE 1 is a front perspective view of a long yardage tape core formed in accordance with this invention; FIGURE 2 is an end view of the core of FIGURE 1;

FIGURE 3 is a front view of a portion of the tape core disclosing the manner in which a tape is radially wound thereon and crossed over from one eccentric winding surface to the adjacent eccentric winding surface;

FIGURE 4 is a top view of the tape core of FIGURE 3 with tape being wound thereon;

FIGURE 5 is a vertical sectional view through the roll carrying core of FIGURE 6 illustrating the manner in which the tape is wound into radially wound rolls across the core;

FIGURE 6 is a front view of the core filled with radially wound rolls of tape; and

FIGURE 7 is a schematic representation of the eccentric winding paths provided by the core.

Referring now to the drawings in detail, a long yardage tape core made in accordance with this invention is designated in its entirety by the numeral 10. The core 10 comprises an axially elongated cylindrical tube 12 having ribs 14 extending from the outer cylindrical surface 13 thereof.

Each of the ribs 14 is approximately perpendicular to the cylindrical core tube axis and extends partially around the outer cylindrical surface 13; adjacent ribs 14 are disposed on diametrically opposite sides of the outer cylindrical surface 13 of the tube 12. Each ribbed section provides an eccentric tape winding surface 36 (FIG. 7), each rib 14 having a tape carrying surface 16, the major portion of the length of which forms a major are 30 (FIG. 7) of each eccentric winding surface radially outwardly spaced from and generally concentric with the cylindrical outer surface 13 of the tube 12. The end portions of each rib 14 are tapered inwardly as at 18 and provide connecting surfaces 32 (FIG. 7) which smoothly join the major are 30 provided by each rib surface 16 and the minor are 34 (FIG. 7) provided by the portion of surface 13 remaining uncovered by the rib with one another which completes the eccentric winding surface 36.

As will be noted particularly in FIGURE 2, the end portions 18 of the ribs join the outer surface 13 of the tube 12 at an angle approximately tangential thereto with the juncture of the end portions 18 with the inter mediate portion of each rib being gently curved so that the tape carrying surfaces 16 of the ribs present no sharp edges as they blend into the outer surface 13 of the core tube 12.

Utilizing a 6% inch outside diameter core tube 12, and a /2 inch rib height, the major are 30 provided by the tape carrying surface 16 of each rib 14, which is outwardly concentric to and generally parallel with the outer surface 13 of the cylindrical tube 12, for optimum utility, extends approximately around the core tube 12, as illustrated in the preferred embodiment, with the ribs being disposed approximately perpendicular to the core axis and being equidistantly spaced from one another. The angular length of the minor are 34 is also 150. As is most clearly illustrated in the schematic representation of FIGURE 7, adjacent ribs are out of phase with one another so that the ribs are axially staggered along the length of the core.

Optimum benefits of this core construction are achieved, regardless of core tube diameter and rib height, by providing the longest possible equal angular length of the major and minor arcs of each eccentric winding surface without rib overlap and with adjacent arcs of adjacent Winding surfaces being diametrically opposite one another and While maintaining the connecting surfaces joining the major and minor arcs of each eccentric winding surface approximately tangential to the minor arc. In this connection it should be noted that the connecting surface, in the case where adhesive exposure is not a problem, may comprise the first layer of a tape web being radially wound on the eccentric winding surface.

Thus, the angular length of the arcs is subject to considerable variance, being longer as the rib radius approaches the core tube radius (as the rib gets thinner) and shorter as the rib radius projects beyond the core tube radius (as the rib gets thicker).

A minimum overlap of end portions of adjacent ribs 14 provides the smallest cross-over angle as a tape web is shifted from one rib to the next. Thus, the shortest tangential line joining the major portion of the tape carrying surface 16 to the outer surface 13 of the tubular core 12 is the most efficient. It has been found that the maximum length of the concentric major portion of each rib surface 16 and minimum rib overlap is provided when the ribs begin to curve inwardly toward the core about 15 from a diameter drawn between the diametrically opposite points of overlap of adjacent ribs with one another as shown in FIGURE 7. The desirability for this construction will become more apparent hereinafter with reference to FIGURE 3.

Referring now to FIGURE 3, which discloses in front elevation the core 10 of FIGURE 1, the process of winding a radially wound roll of tape thereon is disclosed. Beginning at one end of the core 10, tape is Wound in radial fashion on the first eccentric winding surface 36 formed by the first rib 14 and the portion of outer surface 13 of the core tube 12 which the rib surface joins to provide an eccentrically radially wound roll 20 on the first eccentric winding surface 36 wound to the exact height on the minor arc 34 thereof of the major arc of the tape carrying surface 16 of the rib 14 of the next adjacent eccentric winding surface 36. At this point the tape web 22 is shifted by the smallest cross-over spiral angle possible to the next adjacent rib 14 in the manner shown and thence wound upon the next adjacent eccentric winding surface 36 until the height of the eccentric radially wound roll 20 on the second winding surface 36 of the core 10 reaches the height of the major are 30 of the tape carrying surface 16 of the next adjacent rib whereupon the tape web is again transferred and radially wound. This procedure is repeated across the core 10 until all of the ribbed sections are so covered.

Viewed from the top as in FIGURE 4 the eccentrically radially wound roll on each ribbed section of the core 10 appears to rise twice as high on the tube core 12 on one side as it does on the other and indeed this is-the case due to the eccentric winding core surface formed by each rib 14.

As illustrated in FIGURE 6, a continuous strip of tape provides a plurality of eccentrically radially wound rolls 24 spaced along the core all forming part of a single tape roll, being connected to one another by means of the transfer web portions 22 of the tape during Winding.

The manner in which this occurs is most clearly shown in FIGURE 5 wherein the sequence of the radial windings and the transfer or cross-over direction of the spiral web 22 connecting the rolls to one another is illustrated by numbers 1 through 10, to show how the eccentric rolls 24 on each ribbed section can be built up. Thus, the first radially wound roll portion, with the number 1, is wound upon the first eccentric winding surface until the height of this first eccentrically wound roll portion on the outer surface 13 of the core tube 12 reaches the height of the next adjacent rib 14 whereupon it is transferred in the direction illustrated by the arrows 26 to the second eccentric winding surface to form roll portion 2, and thence the web is transferred to the next eccentric winding surface and the procedure repeated through roll portion 5. Then roll portion 6 is wound as a continuation of roll portion 5 to the height of roll portion 4 on the minor arc of the adjacent roll and the process repeated in the direction of arrows 28 to roll portion 10' and tape end 38. The transfer direction from each ribbed section to the next is illustrated with directional arrows. This sequence of winding may be repeated as often as required.

As is apparent from the foregoing, the longer the major are 30 and the less overlap of adjacent major arcs, the smaller may be the angle of transfer of the tape from one ribbed section of the core to the next thereby minimizing any chance of wrinkling as the tape web is transferred from rib section to rib section. Further, since a transfer is necessary only as each eccentrically radially wound roll portion must be begun on each new ribbed section of the core, the points of possible ravelling, a particular problem with filament tapes, are reduced to a minimum while still providing long tape yardage continuity.

While the long yardage tape core 10 is illustrated in the cross sectional views to be formed of a molded or otherwise integrated plastic shape, it is to be understood that the ribs may be applied separately to preformed paper cores or the like and may be of any suitable material, as may be the core tube.

From the foregoing description, the invention will be apparent tothose skilled in the art, however, since numerous minor modifications and changes Will occur from time to time it is not desired to limit the invention to the exact construction shown and described and all such modifications are included which are comprehended by the appended claims.

I claim:

l. A long yardage tape core having an outer surface comprising a plurality of eccentric continuous tape winding surfaces disposed in side by side relation to one another and upon each of which tape can be wound in radially wound roll form, the major arcs of adjacent eccentric surfaces being staggered relative to one another whereby as tape is radially wound on one eccentric sur face to a height on the minor arc thereof equal to the height of the major arc of the adjacent eccentric winding surface the tape can be smoothly crossed over to the major arc of such adjacent winding surface and radially wound thereon while maintaining the continuity of the tape web.

2. A long yardage tape core having a cylindrical outer surface, ribs on said outer surface extending partially therearound and forming side by side ribbed sections, the ribs of adjacent sections being disposed in staggered relation to one another axially along said outer surface providing axially staggered adjacent eccentric winding surfaces whereby tape can be radially wound on each eccentric winding surface to a height on the cylindrical outer surface of said winding surface to the height of the rib of the adjacent eccentric winding surface and thence crossed over on said adjacent rib and similarly wound on said adjacent winding surface.

3. A long yardage tape core having a cylindrical outer surface, ribs on said outer surface extending partially therearound and forming side by side ribbed sections, the ribs of adjacent sections being disposed in staggered relation to one another axially along said outer surface providing axially staggered adjacent eccentric winding surfaces whereby tape can be radially wound on each eccentric winding surface to a height on the cylindrical outer surface of said core to the height of the rib of the adjacent eccentric winding surface and thence crossed over on said adjacent rib and similarly wound on said adjacent winding surface, the top of each of said ribs comprising the major arc of each eccentric winding surface, the intermediate portions of the tops of said ribs being concentrically outwardly spaced from and generally paralleling said cylindrical outer surface, the end portions of said ribs being tapered and each said rib top smoothly joining the exposed curved portion of said cylindrical outer surface comprising the minor arc of each eccentric winding surface.

4. A long yardage tape core having a cylindrical outer surface, ribs on said outer surface extending partially therearound and forming side by side ribbed sections, the ribs of adjacent sections being disposed in staggered relation to one another axially along said outer surface providing axially staggered adjacent eccentric winding surface whereby tape can be radially wound on each eccentric winding surface to a height on the cylindrical outer surface of said core to the height of the rib of the adjacent eccentric winding surface and thence crossed over on said adjacent rib and similarly wound on said adjacent winding surface, the top of each of said ribs comprising the major arc of each eccentric winding surface, the intermediate portions of the tops of said ribs being concentrically outwardly spaced from and generally paralleling said cylindrical outer surface, the end portions of said ribs being tapered and each said rib top smoothly joining the exposed curved portion of said cylindrical outer surface comprising the minor arc of each eccentric winding surface, said ribs being disposed at right angles to said core axis and being equidistantly spaced from one another.

5. A long yardage tape core having a cylindrical outer surface, ribs on said outer surface extending partially therearound and forming side by side ribbed sections, the ribs of adjacent sections being disposed in staggered relation to one another axially along said outer surface providing axially staggered adjacent eccentric winding surfaces whereby tape can be radially wound on each eccentric winding surface to a height on the cylindrical outer surface of said core to the height of the rib of the adjacent eccentric winding surface and thence crossed over on said adjacent rib and similarly wound on said adjacent winding surface, the top of each of said ribs comprising the major arc of each eccentric winding surface, the intermediate portions of the tops of said ribs being concentrically outwardly spaced from and generally paralleling said cylindrical outer surface, the end portions of said ribs being tapered and each said rib top smoothly joining the exposed curved portion of said cylindrical outer surface comprising the minor arc of each eccentric winding surface, said ribs being disposed on diametrically opposite sides of said cylindrical outer surface and having their tapering end portions overlapping one another.

No references cited. 

